This invention relates to emission controls for vehicles powered by internal combustion engines, and more particuarly to a Diesel engine exhaust particulate trap and regeneration system.
Due to the increase in pollution control, federal and state governments have adopted stringent new standards for particulate emissions for all Diesel powered road vehicles. These new standards necessitate a new device in the Diesel engine exhaust system to remove the particulate. Such exhaust treatment is typically envisioned to consist of a filter or trap to collect the particulate from the exhaust gases. Associated with these filters or traps must be a system for periodically disposing of the filtered particulate. Periodic disposal of the filtered particulate is required because the particulate in the filter increase the engine exhaust back pressure thereby adversely affecting the fuel economy and vehicle performance. The most promising means of disposal of the particulate is by burning.
In order to burn the filtered particulate it is necessary to increase the exhaust gas temperature in the filter or trap. Under typical operation, Diesel engine exhaust temperature high enough to burn the particulate cannot be achieved. Therefore, a separate device is required to provide sufficient heat to burn the accumulated soot and maintain acceptable exhaust back pressure levels for good engine and turbocharger performance.